In cigarette packing, a variable-capacity FIFO (First In First Out) cigarette store is interposed between a cigarette manufacturing machine and a packing machine to compensate for any difference between the number of cigarettes produced and the number of cigarettes packed.
One example of a variable-capacity FIFO cigarette store is described in Patent EP-0738478-B1, U.S. Pat. No. 5,413,213-A1, Patent Application WO-9944446-A1, Patent Application WO-02085144-A1, and Patent Application WO-03026988-A1, in which the store comprises an input station and an output station arranged in series along a cigarette feed path; an endless conveyor belt having a conveying branch and a return branch; and an adjusting device for adjusting the lengths of the conveying and return branches in complementary manner. The conveyor belt is powered by at least one electric motor to feed the cigarettes along the conveying branch, and engages a number of fixed guides for maintaining the conveyor belt in the desired position. The conveying branch of the store receives a stream of cigarettes from an output conveyor of a manufacturing machine connected to the store at the input station, and releases a stream of cigarettes onto an input conveyor of a packing machine connected to the store at the output station.
Both the manufacturing and packing machine have respective cigarette reject stations controlled by sensors, which check the quality of the cigarettes passing through and command rejection of any cigarettes or groups of cigarettes not conforming with specifications. The cigarette reject stations can also be operator-controlled manually, regardless of the sensor signals, to eliminate given portions of current production. Manual operator control of the cigarette reject stations (particularly on the packing machine) is adopted, for example, when making size changes on the manufacturing machine, which normally involves eliminating the cigarettes produced just before and after the size change.
Manual operation of the cigarette reject stations is a complex, difficult job, even for a skilled operator, owing to the difficulty involved, mainly on account of the high speed at which the cigarettes are fed through the machines, in communicating to the packing (or manufacturing) machine the exact moment in which to perform the reject operation.